Sanctus

Sanctus, more commonly known by his followers as "His Holiness", is the leader of the Order of the Sword, the Vicar of Sparda, a previous Supreme General of the Holy Knights and the main antagonist of Devil May Cry 4. As the leader of Fortuna, he is behind all of the actions of the Order, and is the mastermind of their plot to conquer the world using The Savior. He is considered one of the greatest leaders of the Order, and has the total loyalty of the populace.

Appearance
Before undergoing Ascension Ceremony, Sanctus appears as an elderly man in Vicar's clothes. However, this mild and frail appearance masks his nefarious, power-hungry and calculating personality. As Sanctus Diabolica, his appearance changes drastically, taking on demonic and wicked features, such as horns and wings of energy tendrils.

Personality
Sanctus' most notable trait is his hunger for power, doing whatever it takes to attain greater power and have it under his command. Due to this, he is extremely manipulative, as seen when he manipulates the whole city of Fortuna, including the very members of the Order into his ways. He is also ruthless, cruel and does not care about the methods he uses; in fact, without hesitation, he used Kyrie despite the fact that she was the sister of Credo, who was extremely loyal to him. He also does not care about the citizens who could die as a result of the demons he summoned for his plans.

He thinks quite highly about himself as the leader he is, and he also commands the Savior as well as being the most powerful Ascended being. Ironically, he is incredibly cowardly as he prefers to let his henchmen do his bidding. He also hides using his manipulated Alto Angelo while he is inside the Savior. He could also be described as somebody who is desperate for victory as seen when he used Kyrie to make sure Agnus activates the true Hell Gate, as well as fusing himself with the Savior as a last ditch effort to defeat Nero (which failed miserably as he made the Savior weaker). He can also be described as sadistic to some point as he constantly laughs while finding it absurd that both Nero and Credo fight for love nonetheless using this for his evil agenda.

Despite his vile nature Sanctus is also surprisingly pragmatic and intelligent, able to devise a plot without anybody (save for Lady) noticing, as well as deduce the true identity of Gloria. He also seems to value his subordinates according to their usefulness and comparative evil to him, shown in how he's far less moved to disrespect Agnus, a scientist with no qualms about doing research with demonic powers which greatly aided Sanctus' plans, as opposed to Credo, who cares a lot about his sister as well as being mainly a fighter.

Strategy
Both fights are basically the same, although after acquiring Sparda, Sanctus becomes slightly more powerful.

Devil May Cry 4
Sanctus is killed by Dante during a sermon, but is later resurrected through the Ascension Ceremony. Unlike the other ascended knights, he initially retains his original form after the ceremony, while gaining incredible demonic power.

Sanctus originally planned to use Dante as the Savior's core, and had the Order take the Yamato and open the Hell Gates as a method of luring Dante to Fortuna. However, when Agnus reveals to the Order that Nero possesses demonic power, Sanctus orders him to kidnap Kyrie, Nero's love interest, in order to lure Nero to the Savior and use him instead. Though he is unable to convince Nero to be absorbed willingly, he is able to overpower and absorb him anyway, in the process, recovering the Yamato which Nero had taken. During the activation of the Savior, he is also attacked by Credo, who considers Sanctus's exploitation of Kyrie to be a betrayal, but Sanctus mortally wounds him with Yamato. As Credo falls down, he is caught by Dante, who came in along with Trish. Sanctus isn't surprised with her appearance, and claims that he knew that Trish was actually Gloria. He then declares that the awakening of the Savior cannot be stopped anymore. And indeed, they fail in stopping it, despite Nero's attempt to smash Sanctus with Devil Bringer's power. As Nero is absorbed completely, The Savior awakens and flies away, along with Sanctus.

Shortly after, Agnus opens the true Hell Gate, which resided in Fortuna, causing total havoc in the city. In this chaos, the Order's knights come to "save" the people from demons, and shortly after, the Savior itself appears in the sky above Fortuna, eradicating all demons with its power. Sanctus declares that they should not fear, as the Savior will deliver them salvation.

Much later, after Dante takes Yamato from Agnus and destroys the true Hell Gate, Dante is confronted by Sanctus in Alto Angelo form. He destroys this demon, revealing it to be nothing more than an empty puppet, and proceeds to attack the Savior to get at the real Sanctus, who is inside. While not able to enter himself, he is able to weaken the statue enough for Nero to escape, and returns the Yamato to him. Nero proceeds through the statue to the Sacred Heart, where he encounters Sanctus in his fully ascended form — Sanctus Diabolica.

After defeating this form of Sanctus, Nero is able to rescue Kyrie and escape from the Savior. As they return to town, the Savior reawakens as the False Savior by merging with Sanctus's remains, and taking on his face. However, it is much weaker than it was earlier, and Nero is able to easily overpower it with his Devil Bringer. As it tries to rise back up, Nero seizes its face in his Devil Bringer and crushes it.

Powers & Abilities
Of all the members of the Order of the Sword to appear, Sanctus is the only one who is known to be completely human - before being killed. However, the Ascension Ceremony revives his corpse and grants him demonic powers.

Demonic Powers
At first, Sanctus didn't undergo any drastic physical transformation. Shortly after becoming one with The Savior, his powers had increased dramatically and he had received the ability to teleport, levitate, and encase himself in a protective shield. In the form of attacks, he unleashes torrents of energy blasts that grind against the ground and beams of energy that rain from the sky.

While the demonic energies have decreased his degrading vitality as an elderly man and given him superhuman endurance, he is still human, and thus, more susceptible to attacks that a demon would merely flinch at. He is also shown to take telepathic possession of the armor of an Alto Angelo twice. In the end, despite being empowered by the massive demonic energies contained within Sparda's sword, Sanctus' power still falls short of Nero. Although his corrupted soul is one with The Savior, he actually ends up weakening the colossus and is overpowered and killed by Nero with ease.

Sanctus Diabolica
Sanctus Diabolica (魔皇サンクトゥス) is the fully Ascended form of Sanctus. He is encountered by Nero within The Savior's Sacred Heart, during Mission 20: La Vita Nuova. In this form he is fused with all the fiendish powers of Hell and is able to resonate with the Sword of Sparda he wields, amplifying his power and warping his form into a Hellish visage: horn-like appendages on his back which sprout fiery wings, a jewel on his forehead resembling The Savior's, and the angelic halo-like horns of Ascended Humans.

Background
The Sanctus ("Holy, Holy, Holy" in Latin) is the fourth part of the Catholic Ordinary of the Mass. It is traditionally sung in Latin.